White luminescence

Exhibitor

Product description

Wherever energy-efficient light engineering is required, light diodes consisting of organic material, so-called OLEDs, are often used. Light diodes emitting white luminescence are in particularly high demand. In addition, lasers either emitting white luminescence or whose colour can be set offer interesting options for application in science and technology.One way to create white luminescence is to use three lasers emitting red, green and blue light respectively that is mixed into white laser light with the aid of very thin glass fibres. The disadvantages of this technology are its very high costs arising from the use of several lasers and the difficult handling of the glass fibres. Alternatively, lasers are applied whose light-emitting medium consists of a mixture of gases, with each gas creating light of a different colour. Once a certain mixing ratio of the gases is achieved, the laser will then emit white light. However, the disadvantage here is that the different gases absorb part of the radiation, which reduces the efficiency and the luminous intensity of the laser. KIT scientists have developed a colouring agent that can be excited to turn luminescent by being irradiated with light. The emission spectrum shows at least three narrow maxima of luminescent intensity that are clearly separated from one another. These maxima, which are also called emission bands, lie within the range of visible light, and each of them has a different colour. Used in a laser, the compound creates white light through mixing the coloured emissions. Since the light-emitting laser medium consists of only one single substance, there are hardly any losses through absorption. So the laser features a high lumen output. Furthermore, it is easy technically to filter out individual emission bands and thus set the colour of the laser. For manufacturing OLEDs, the colouring agent can also be excited to emit light with an electric potential and then be processed with a low-cost printing method.